Manual ISR not revalidating all domains (why does it need to do more than one domain?)

[Noitidart]

I recently added a domain to my Next.js app on Vercel. My old URL was foo-bar.vercel.app. And now it is nice.com (examples). I notice that my res.revalidate('/page') now is making a call to revalidate https://nice.com/page. And visting my old https://foo-bar.vercel.app/page is showing outdated info. Why is this? Shouldn't both domains point to the exact same resource/page? Do I have to make revalidate also revalidate my old domain?